Mobile telephone devices are provided with a color liquid crystal display as a display device for displaying thereon a standby screen, and a transmission/reception screen, etc., in a telephone mode, and the luminance of a displaying can be set on its menu screen, for example. Moreover, the sound volume of a ringtone, too, can be set on the menu screen. These settings adjust the driver of the display and the amplifier of a speaker. Furthermore, in recent years, there has been proposed a mobile telephone device provided with a television broadcast-viewing function (see Japanese Patent Laying-open H11-184576), in which video based on broadcast reception is supplied to the driver of the display, and audio based on the broadcast reception is supplied to the amplifier of a speaker.